SPECIAL REPORT
LEEDuser expert
emily reese moody
LEED AP BD+C, LFA, EcoDistricts AP, ENV SP, Fitwel Ambassador, WEDG Professional, ActiveScore AP, GGP, GPCP, GCP
Jacobs
Sustainability Director, Certifications & Compliance
SPECIAL REPORT
LEEDuser’s viewpoint
Frank advice from LEED experts
LEED is changing all the time, and every project is unique. Even seasoned professionals can miss a critical detail and lose a credit or even a prerequisite at the last minute. Our expert advice guides our LEEDuser Premium members and saves you valuable time.
Credit language
© Copyright U.S. Green Building Council, Inc. All rights reserved.
Intent
To minimize effects on microclimates and human and wildlife habitats by reducing heat islands.
Requirements
Have in place strategies to minimize the project’s overall contribution to heat island effects and that meet the following criterion:
|
Area of Nonroof Measures |
|
Area of High-Reflectance Roof |
|
Area of Vegetated Roof |
|
Total Site Paving Area |
|
Total Roof Area |
|
———— |
+ |
—————— |
+ |
—————— |
≥ |
+ |
||
|
0.50 |
|
0.75 |
|
0.50 |
|
|
Alternatively, an SRI and SR weighted average approach may be used to calculate compliance. Use any combination of the following strategies.
Nonroof Measures
- Plants that provide shade over paving areas (including playgrounds) on the site. For newly installed plants, base shade area on 10-year canopy width at noon.
- Vegetated planters.
- Shade with structures covered by energy generation systems, such as solar thermal collectors, photovoltaics, and wind turbines.
- Shade with architectural devices or structures that have a three-year aged solar reflectance (SR) value of at least 0.28. If three-year aged value information is not available meet an initial SR of at least 0.33.
- Shade with vegetated structures.
- Paving materials with a three-year aged solar reflectance (SR) value of at least 0.28. If three-year aged value information is not available, meet an initial SR of at least 0.33.
- Open-grid pavement system (at least 50% unbound).
High-Reflectance Roof
Roofing materials with an SRI equal to or greater than the values in Table 1. Meet the three-year aged SRI value if available, otherwise, meet the initial SRI value.
Table 1. Minimum solar reflectance index value, by roof slope
| Slope | Initial SRI | 3-year aged SRI | |
|---|---|---|---|
| Low-sloped roof | ≤ 2:12 | 82 | 64 |
| Steep-sloped roof | > 2:12 | 39 | 32 |
Roof area that consists of functional, usable spaces (such as helipads, recreation courts, and similar amenity areas) may meet the requirements of nonroof measures. Applicable roof area excludes roof area covered by mechanical equipment, solar energy panels, skylights, and any other appurtenances.
Vegetated Roof
If newly installed, sufficient growing medium and plant material must be in place to provide full vegetative cover within 3-years. Have in place a maintenance program that ensures all high-reflectance surfaces are cleaned at least annually to maintain good reflectance, all vegetation is maintained for plant health, and any vegetated structures or vegetated roofs are maintained for good structural condition.
See all forum discussions about this credit »What does it cost?
Cost estimates for this credit
On each BD+C v4 credit, LEEDuser offers the wisdom of a team of architects, engineers, cost estimators, and LEED experts with hundreds of LEED projects between then. They analyzed the sustainable design strategies associated with each LEED credit, but also to assign actual costs to those strategies.
Our tab contains overall cost guidance, notes on what “soft costs” to expect, and a strategy-by-strategy breakdown of what to consider and what it might cost, in percentage premiums, actual costs, or both.
This information is also available in a full PDF download in The Cost of LEED v4 report.
Learn more about The Cost of LEED v4 »Frequently asked questions
|
What's the difference between SR and SRI? The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
Addenda
Can v4 projects use typical solar reflectance (SR) values, or data from a previous project, for documentation of hardscape materials?
The following typical SR values can be used for standard nonroof materials, in lieu of project-specific testing data:
Typical Solar Reflectance Values for Standard Nonroof Materials
Gray cement concrete- Initial Solar Reflectance: 0.26, Three-Year Aged Solar Reflectance*: 0.18
White cement concrete- Initial Solar Reflectance: 0.70, Three-Year Aged Solar Reflectance*: 0.35
Asphalt concrete- Initial Solar Reflectance: 0.05, Three-Year Aged Solar Reflectance*: 0.10
*Three-year aged SR values are based on no cleaning.
Alternatively, documentation showing that the current concrete mix and sealant are equivalent to a tested mix and sealant from a previous project is acceptable, provided that all ingredients are the same and have not changed.
Documentation toolkit
The motherlode of cheat sheets
LEEDuser’s Documentation Toolkit is loaded with calculators to help assess credit compliance, tracking spreadsheets for materials, sample templates to help guide your narratives and LEED Online submissions, and examples of actual submissions from certified LEED projects for you to check your work against. To get your plaque, start with the right toolkit.
Get the inside scoop
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© Copyright U.S. Green Building Council, Inc. All rights reserved.
Intent
To minimize effects on microclimates and human and wildlife habitats by reducing heat islands.
Requirements
Have in place strategies to minimize the project’s overall contribution to heat island effects and that meet the following criterion:
|
Area of Nonroof Measures |
|
Area of High-Reflectance Roof |
|
Area of Vegetated Roof |
|
Total Site Paving Area |
|
Total Roof Area |
|
———— |
+ |
—————— |
+ |
—————— |
≥ |
+ |
||
|
0.50 |
|
0.75 |
|
0.50 |
|
|
Alternatively, an SRI and SR weighted average approach may be used to calculate compliance. Use any combination of the following strategies.
Nonroof Measures
- Plants that provide shade over paving areas (including playgrounds) on the site. For newly installed plants, base shade area on 10-year canopy width at noon.
- Vegetated planters.
- Shade with structures covered by energy generation systems, such as solar thermal collectors, photovoltaics, and wind turbines.
- Shade with architectural devices or structures that have a three-year aged solar reflectance (SR) value of at least 0.28. If three-year aged value information is not available meet an initial SR of at least 0.33.
- Shade with vegetated structures.
- Paving materials with a three-year aged solar reflectance (SR) value of at least 0.28. If three-year aged value information is not available, meet an initial SR of at least 0.33.
- Open-grid pavement system (at least 50% unbound).
High-Reflectance Roof
Roofing materials with an SRI equal to or greater than the values in Table 1. Meet the three-year aged SRI value if available, otherwise, meet the initial SRI value.
Table 1. Minimum solar reflectance index value, by roof slope
| Slope | Initial SRI | 3-year aged SRI | |
|---|---|---|---|
| Low-sloped roof | ≤ 2:12 | 82 | 64 |
| Steep-sloped roof | > 2:12 | 39 | 32 |
Roof area that consists of functional, usable spaces (such as helipads, recreation courts, and similar amenity areas) may meet the requirements of nonroof measures. Applicable roof area excludes roof area covered by mechanical equipment, solar energy panels, skylights, and any other appurtenances.
Vegetated Roof
If newly installed, sufficient growing medium and plant material must be in place to provide full vegetative cover within 3-years. Have in place a maintenance program that ensures all high-reflectance surfaces are cleaned at least annually to maintain good reflectance, all vegetation is maintained for plant health, and any vegetated structures or vegetated roofs are maintained for good structural condition.
In the end, LEED is all about documentation. LEEDuser’s Documentation Toolkit, for premium members only, saves you time and helps you avoid mistakes with:
- Calculators to help assess credit compliance.
- Tracking spreadsheets for materials purchases.
- Spreadsheets and forms to give to subs and other team members.
- Guidance documents on arcane LEED issues.
- Sample templates to help guide your narratives and LEED Online submissions.
- Examples of actual submissions from certified LEED projects.
|
What's the difference between SR and SRI? The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
Can v4 projects use typical solar reflectance (SR) values, or data from a previous project, for documentation of hardscape materials?
The following typical SR values can be used for standard nonroof materials, in lieu of project-specific testing data:
Typical Solar Reflectance Values for Standard Nonroof Materials
Gray cement concrete- Initial Solar Reflectance: 0.26, Three-Year Aged Solar Reflectance*: 0.18
White cement concrete- Initial Solar Reflectance: 0.70, Three-Year Aged Solar Reflectance*: 0.35
Asphalt concrete- Initial Solar Reflectance: 0.05, Three-Year Aged Solar Reflectance*: 0.10
*Three-year aged SR values are based on no cleaning.
Alternatively, documentation showing that the current concrete mix and sealant are equivalent to a tested mix and sealant from a previous project is acceptable, provided that all ingredients are the same and have not changed.
LEEDuser expert
emily reese moody
LEED AP BD+C, LFA, EcoDistricts AP, ENV SP, Fitwel Ambassador, WEDG Professional, ActiveScore AP, GGP, GPCP, GCP
Jacobs
Sustainability Director, Certifications & Compliance
